Upgrading from an Aerotec 380. Looking for a good sea keeping boat with a nice deep hull. For two adults and two kids + occasional guests. Want a four stroke engine. 4.8m absolute max length. Thinking an Ribcraft 4.8, Ribquest 4.8, SR 4/4.7 or similar ....

Ribcraft 4.8m with Yamaha F60 or Suzuki DF60 (only 110kg) is nice balance. Two person jockey console works well. Few examples on used market just now. 5 year warranty on boat if you buy new. Tubes are hypalon. Ribcraft 4.8 Used Boat for Sale | TheYachtMarket

Don't think I've seen a second-hand Ribquest 4.8m in 4 years of looking. I visited Ribquest when Dave Rose was running things in Sheffield. Quality boat in Orca fabric. Can take up to 70hp, so new Yamaha F70 would be option, but not cheap.

Searider 4.7m - can't comment. Has loyal following here and justifiably so. Someone will give you low-down on best match engine wise and seating configuration.

The RIB you've linked caught my eye as well. I think it is over priced though. Having been commercially used, there is no warrantee left, the tubes are a bit faded, and she is generally a bit unloved for such a youngster.

I missed one Ribcraft had for brokerage which would have been a better bet.